Piston pump



Nov. 9, 1948.

H. I w. ROCKWELL 2,453,266

2 Shoots-Shoot 1 Filed Feb. 9, 1945 L n Emma: T 1

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Patented Nov. 9, 1948 rrs'ron PUMP Harvey W. Rockwell, Cedar Rapids, Iowa, assignor to La Plant-Choate Mfg. Co. Inc., Cedar 'Raplds, Iowa, a corporation of Delaware Application February 9, 1945 Serial No. 578,941

6 Claims. (Cl. 103-462) This invention relates to a pump and the method of operating the same at a desired efficiency despite the existence of heretofore considered irreconcllable factors.-

The pump hereinafter described is of the piston type and while certain aspects of the invention contribute particularly to the eflicient operation of this type of apparatus it nevertheless should immediately be appreciated that other types of pumping apparatus also may be operated more efficiently in connection with the hereinafter described invention.

The invention is hereinafter described in connection with the accompanying drawings, in which Fig. 1 is a plan view of a pump embodying the invention;

Fig. 2 is an elevational sectional view taken the line 22 of Fig. 1;

Fig. *3 is a plan sectional view taken on the line 3--3 of Fig. 2;

Fig. 4 is an elevational sectional view taken on the line 4- -4 of Fig. 2/; I

Fig. 5 is a fragmentary elevational view of the piston end of the rotor member of the pump; and

Fig. 6 is an elevational sectional view of a modifled form of rotor member. I

A casing frame or cage I0 is formed with the various interior chambers as best shown in sectional views of Figs. 2, 3 and 4. The interior of the casing in is adapted to receive a rotor H and shaft Ila (the two being associated by key Ilb), it being observed that the shaft and rotor unit are mounted so that the left-hand end of the rotor is directly supported (Fig. 3) one bearing i2 whilethe right-hand end of the shaft is carried in a bearing I3. The hearing it is mounted interiorly centrally of a bell closure member l4 bolted at [5 and 16 to the casing Ill. The lefthand side of'the casing is closed by a closure plate I! bolted at l8 and i9 to the casing i0.

An important feature of.this invention arises from the fact that the bearing member I2 is mounted initially directly on the rotor H (as best illustrated in Fig. 3) whereafter the rotor member and associated bearing l2 are slipped into position. This results in the bearing member l2 making such a predetermined fit with the interior of the casing ID as to permit rotation of the rotor within the indicated space with a much smaller clearance than was heretofore possible when such rotors were supported at opposite ends of the rotor shaft rather than as herein indicated.

, a1 and as.

2 Inasmuch as the herein described pumping unit may be used in a hydraulic pumping unit assembly as illustrated in the co-pending application of Harvey W. Rockwell, Serial No. 580,121,

filed February 28, 1945. the intake and outlet passages of the herein described pumping unit are illustrated in such design configuration as to be capable of connection with certain valve assembly unit passages illustrated in said co-pending application. This. however, should not be understood as alimitation in the use of the herein described piston pump. the openings from and into the inlet and outlet passages being of course capable of relocation as required by thespcclflc problems encountered in any field wherein the herein described pumping unit may be used. Accordingly openings 20 and 2i at the top of the pump casing let into passages 22 and 23. respec- 28 and 29 respectively (Fig. 3) and thence lead through ports 30 and 3| into the lowermost portion 32 of the pump casing. A plug 38 is disposed in the lower portion of said chamber 32 to permit ready disposal of fluidtherei'rom should it become necessary.

The rotor surface and the bottom substantially semi-circular wall 34a of the casing define a chamber 34 into which fluid may pass from chamber 32 via the semi-annular passage 35. The upper portion of the rotor I I forms the bottom and the walls 26 and 21 the sides ofa' pump outlet passage or chamber 36. The front and back of said outlet chamber 38 comprise the cage walls A relief valve 39 is urged by spring 40 to the left normally to close relief port H which latter connects the outlet passage 38 and the inlet chamber 32. The valve 89. the spring 40 and a spring-containing member 42 are disposed in an opening which is closed by a cap 42.

The rotor II is longitudinally recessed to provide a plurality'of piston-receiving openings 44 in each of which a piston 45 is snugly fitted to move longitudinally of the rotor. The pistons 48 are moved to the right by springs 48 nested within the pistons as shown in Fig. 3. At the left- .hand end of each of the cylindricalpiston-receiving openings 44 is a longitudinally extending chamber 41 and a radially extending passage 48, the latter connecting the space 44 with the exterior-of the rotor I I. The ends 48 of the pistons 45 are conically shaped to bear flush against a 3 thrust-or wobble plate 5 which latter a in a ball bearing housed in the interior of the cage or bearing housing I4.

It should be noted that the novel manner of associating the bearing I! with the rotor makes it possible to construct the bearings l2 and ii of substantially equal size thereby to take care of the reactionary thrusts set up by the pump operation. This particular structure is of marked advantage in an apparatus as here described and is made the subject matter of subcombination claims. The mounting of the wobble plate in the manner shown provides for exceptionally low frictional resistance during operation and at the same time the wobble plate comprises a thrust bearing or plate.

From the foregoing it will be apparent that as the rotor revolves the pistons 45 move longitudi- V belly of the rotor, being urged constantly by the springs 48 against the thrust plate 50. when fluid is supplied via passages 22 and 24 to the chambers 32 and 84, the suction of the pistons 4 45 draws said fluid into the cylindrical chambers 44 through passages 48 and 41, it being observed that the pistons are moving to the right during the time said ports 48 are connected to the chamber 34. Immediately thereafter, however, when said ports 48 are connected to the outlet chamber 88, the pistons, because of the canted position of .the thrust plate 50, are moved to the left (Fig. 3) against the action of springs 48 to expel the fluid in the chambers 44 outwardly through the ports 48 into the outlet chamber 38.

While the aforedescribed apparatus is a desirable pumping unit because of the high rotating speeds which may be imparted to the rotor and the consequent high rate of operation of the pumping pistons, there is a considerable centrifugal action at the rotor surface when said rotor is operated at a high speed. Accordingly when the fluid is presented to the ports 48 by filling of the chamber 34 it has been observed that said fluid in chamber 34 is not properly drawn into the cylindrical chambers 44 even though the pistons in the latter are in their outermost position, i. e. in the position shown at the bottom of Fig. 3, and at which time the-greatest possible suction is exerted at said openings 48;

Accordingly, one major feature of the heredescribed invention includes the provision of the somewhat restricted semi-circular passage 85 resulting from the formation of a lip 35a interiorly of the bottom wall of. the casing (see- Fig. 2) thus eventuating a narrowed passage through which the fluid may be positively pumped from the receiving chamber 32 into the chamber 34 Such pumpsesame g i K s is mounted 4 than radially, it being intended that the rotor shall be rotated in the direction of the arrow. he.

the passage openings are in advance of the rotation, thereby to increase the efliciency of fluid entrance into said passages.

In all other respects except the arrangement .of the passages 48a the modified rotor Ila is .480 tend to scoop fluid out of the chamber 38 and thus the inertia of the fluid tends to force the fluid into the cylinders along the inclined passages.

While I have shown particular embodiments of my invention, it will beunderstood, of course, that I do not wish to be limited thereto since many modifications may be made, and I.- therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, ,what claim and desire to secure by Letters Patent is:

1. In a piston pump, a casing. a substantially cylindrical rotor rotatably supported in said casing, a plurality of pump cylinders and pistons associated with said rotor, wobble plate-means for reciprocating said pistons upon rotation of said rotor, radial passages in said rotor acting as fluid inlet passages to said cylinders during one portion of the rotation of said rotor and as fluid outlet passages during another portion of said rotation, means forming a confined fluid chamber surrounding a portion of said cylindrical surface of said rotor and communicating with said radial passages when the latter function as inlets to said piston pump cylinders, means'cooperating with said rotor to form a restricted entrance to said confined chamber and means for forcing the-fluid into said conflned chamber with sufficient pressure to overcome the rotors centrifugal force and insure the fluid intake through said passages including impellers carried by said rotor and operating in the entrance to said confined chamber.

2. In a piston pump. a casing. a rotor rotatably supported in said casing, a plurality of pump cylinders and pistons associated with said rotor, wobble plate means for reciprocating said pistons upon rotation of said rotor, radial passages in said rotor acting as fluid inlet passages to said cylinders during one portion of the rotation of said rotor and as fluid outlet passages during another portion of said rotation, means cooperating with the outer surface of said rotor to form a fluid chamber surrounding a portion of the surface of said rotor and communicating with said passageway when the latter function as inlets to said pump cylinders, means extending around a portion of said rotor in spaced relation to the outer.

adjusted angular position, thereby making it possible to set the impeller blades in accordance with the supercharging effect which it is'desired to secure.

I A modified form of rotor i la is illustrated in Fig. 6. The passages 48a in the modified rotor correspond to radially extending passages 48 in the rotor II but are bored at an angle rather surface thereof and cooperating therewith to form an arcuate entrance to said chamber, and radial impeller means associated with said rotor and movable in said arcuate entrance for forcing fluid into'said chamber to supercharge the fluid presentedto said passages during the time they serve as inlets to said pistons, said impeller means comprising vanes seated in radial openings spaced peripherally around said rotor and adapted to be feathered tocontrol the degree of supercharge.

3. In a piston pump, a casing, a substantially cylindrical rotor rotatably supported in said casing, a plurality of pump cylinders and pistons associated with said rotor, wobble plate means for reciprocating said pistons upon rotation of said rotor, said rotor having substantially straight passages therein extending'from said cylinders to the cylindrical surface of said rotor to act as fluid inlet passages during one portion of the rotation of said rotor and as fluid outlet passages during another portion of said rotation, means forming a confined fluid chamber surrounding a portion of said cylindrical surface of said rotor and communicating with said passages when the latter function as inlets to said pump cylinders, means cooperating with said rotor to form a restricted entrance to said chamber, and impellers carried by said rotor and movable in said entrance for forcing fluid into said chamber with sufilcient pressure to overcome the centrifugal force produced by rotation of said rotor and thereby insure proper fluid intake through said passages.

4. In a piston pump, a casing. a substantially cylindrical rotor-rotatably supported in said casing, a plurality of pump cylinders and pistons associated with said rotor, wobble plate means for reciprocating said pistons upon rotation of said rotor, said rotor having substantially straight passages therein extending from said cylinders to the cylindrical surface of said rotor to act as fluid inlet passages during one portion of the,

rotation of said rotor and as fluid outlet passages during another portion of said rotation, means forming a confined fluid chamber surrounding a portion of said cylindrical surface of said rotor and communicating with said passages when the latter function as inlets to said pump cylinders, means cooperating with said rotor to form a restricted entrance to said chamber, and a plurality of impeller blades mounted in circumferentially spaced relation on said rotor and projecting into said entrance for forcing fluid under pressure into said chamber.

5. In a piston pump, a casing. a substantially cylindrical rotor rotatably supported in said casing, a plurality of pump cylinders and pistons associated with said rotor, wobble plate means for reciprocating said pistons upon rotation of said rotor, said rotor having substantially straight passages therein extending from said cylinders to the cylindrical surface of said rotor to act as fluid inlet passages during one portion of the rotation of said rotor and as fluid outlet passages during another portion of said rotation, means forming a confined fluid chamber surrounding a portion of said cylindrical surface of said rotor and communicating with said passages when the reciprocating said pistons upon rotation of said rotor, said rotor having substantially straight passages therein extending from said cylinders to the cylindrical surface of said rotor to act as fluid inlet passages during one portion of the rotation of said rotor and as fluid outlet passages during another portion of said rotation, means forming a confined fluid chamber surrounding a portion of said. cylindrical surface of said rotor and communicating with said passages when the latter function as inlets to said pump cylinders, each of said passageways being angularly disposed to intersect the cylindrical surface of said rotor forwardly of the radial position of the associated cylinder in the direction of rotation of said rotor whereby the rotation of said rotor tends to force fluid into said cylinders when said passages communicate with said chamber, means cooperating with said rotor to form a restricted entrance to said chamber, and impellers carried by said rotor and movable in said entrance for forcing fluid into said chamber with suflicient pressure to overcome the centrifugal force produced by rotation of said rotor and thereby insure proper fluid intake through said passages.

HARVEY W. ROCKWELL.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 415,458 Heckle NOV 19, 1889 1,971,601 Dilg Aug. 28, 1934 1,978,480 Svenson Oct, 30, 1934 2,129,886 Syrovy Sept. 13, 1938 2,295,833 Deschamps Sept. 15, 1942 2,299,233 Hofler Oct. 20, 1942 2,300,009 Rose Oct. 27, 1942 2,331,694 Jeffrey Oct. 12, 1943 2,392,543 Mercier Jan. 8, 1946 

